Vehicle door latch

ABSTRACT

A motor-vehicle-door latch has a pin which is engageable with a lock pawl mounted on the end of a rotatable shaft controlled by the lock mechanism. The pawl is formed with a step ledge subdividing it into a body portion formed with a hole receiving the end of the shaft and a fork portion formed with a recess receiving the lock pin. The body portion is about twice as thick as the fork portion and the step lies at an angle to the median plane of the pawl, an angle between 100* and 105* being preferred. The hole in the body portion has a height in the direction of the median plane substantially equal to the thickness of the body portion and a width orthogonal to this axis which is twice as great. The pawl is made by positioning an elongated metal bar formed with a step ledge under a punch and die having a pawl configuration with a median plane inclined to the longitudinal axis and the direction of rolling of the bar.

United States Patent [191 Watermann VEHICLE DOOR LATCH [75] Inventor: Hans-Dieter Watermann,

Metzkausen, Germany [73] Assignee: Arn. Kiekert Sohne, Heiligenhaus, I

Germany [22] Filed: July 26, 1971 [21] Appl. No.: 166,234

[52] US. Cl. 292/213, 292/216 [51] Int. Cl. E05c 3/26 [58] Field of Search 292/216, 198, 280, DIG. 26,

292/DIG. 27, DIG. 41

Primary Examiner-Richard E. Moore Attorney, Agent, or Firm-Karl F. Ross; Herbert Dubno [57] ABSTRACT A motor-vehicle-door latch has a pin which is engageable with a lock pawl mounted on the end of a rotatable shaft controlled by the lock mechanism. The pawl is formed with a step ledge subdividing it into a body portion formed with a hole receiving the end of the shaft and a fork portion formed with a recess receiving the lock pin. The body portion is about twice as thick as the fork portion and-the step lies at an angle to the median plane of the pawl, an angle between 100 and 105 being preferred. The hole in the body portion has a height in the direction of the median plane substantially equal to the thickness of the body portion and a width orthogonal to this axis which is twice as great. The pawl is made by positioning an elongated metal bar formed with a step ledge under a punch and die having a pawl configuration with a median plane inclined to the longitudinal axis and the direction of rolling of the bar.

3 Claims, 7 Drawing Figures PAIENIEDmzs m4 SHEET 1 [1F 2 F I G o 2 HANS-DIETER WATERMANN INVENTOR.

BY CkaY 1 ATTORNEY PAIENIEDmzsmm afmalfiw SHEET 2 0F 2 HANS'DIETER WATERMANN INVENT'OR.

FIG.7

ATTORNEY VEHICLE DOOR LATCH FIELD OF THE INVENTION The present invention relates to a motor-vehicledoor latch and to a lock pawl for such a latch.

BACKGROUND OF THE INVENTION A motor-vehicle-door latch is known wherein a pin having an enlarged head extends from the edge of the door post and a lock mechanism is provided on the edge of the door engageable with this post to engage and firmly hold this pin. This mechanism often consists of a housing in which a pivotal lock pawl is provided. The pawl is formed at one end with a fork in which the pin is engageable and is mounted at its other end on a rotatable actuating shaft coupled to the operating mechanism. As the door is closed the latch pin engages in the fork while its head is received between the pawl and the latch housing. The pawl and its shaft are caused to rotate until the door closes fully and a detent therein prevents reverse rotation of the shaft, so that the pin lies trapped in the fork and the door is firmly held shut.

It is obvious that a great deal of torque is exerted by the pawl-carrying shaft. To this end the pawl is formed with a throughgoing hole in turn formed with at least one flat. The shaft has a similarly formed end so that maximum rotational coupling is possible. It has been found absolutely necessary to case harden both the pawl and the shaft at least in the region at which they join each other if any reasonable length of service is to be expected from the latch. This last process represents a substantial encumberance in the speedy production of such latches.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an improved latch of the above-described general type.

Another object is to provide an improved lock pawl for such a latch. A further object is to provide a lock pawl of the character described which need not be hardened.

SUMMARY OF THE INVENTION I attain the above objects according to the present invention with a lock pawl which has a body portion formed with the hole that receives the rotatable actuating shaft and a fork portion that is formed with the recess in which the latch pin is engaged in the closed position of the vehicle door. A straight stepped ledge separates these two portions and the body portion has a thickness which is greater, advantageously twice as great, than that of the fork portion. This step lies at an angle to the median plane of the generally elongated pawl, this plane lying basically equidistant from the two long sides of this pawl and perpendicular to the planes of the two parallel parts of the step. In this manner as the door is closed the end of the latch pin strikes the step as well as the base of the pin-receiving recess to rotate the pawl back and lock the door. The inclination of the step in the open position of the latch is such that it forms a camming surface for pivoting of the pawl back into the latched position, and in this latched position it aids in holding the pin back.

The hole through the body portion is, according to this invention, formed with two parallel flat sides extending orthogonal to the median plane. The hole has, in the direction of the plane between the flats, a width substantially less than its width transverse to this axis between its two rounded sides. The width in the direction of the plane is preferably about half the transverse width. The plane passes through the geometric center of this hole. The thickness of the body portion, which like the fork portion is of uniform thickness, is according to the invention substantially equal to the distance between the two flat sides, the first-mentioned hole width.

According to another feature of the present invention, the pawl is stamped out of an elongated rolled profiled metal bar. The necessary punch and die have the elongated outline corresponding to the outline of the pawl are oriented so that the median plane of the pawl lies at an angle of between and to the longitudinal axis of the bar from which these pawls are serially punched and, of course, the rolling direction.

DESCRIPTION OF THE DRAWING The above and other objects, features, and advantages will become apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a perspective view showing the latch according to the present invention;

FIG. 2 is an elevational view of the pawl of this latch;

FIG. 3 is a section taken along line IIIIII of FIG. 2;

FIG. 4 is a top view of the actuating shaft of the latch of FIG. 1;

FIG. 5 is an end view of the shaft of FIG. 4;

FIG. 6 is a top view of a profiled. bar from which the pawl of FIGS. 5 is punched; and

FIG. 7 is a side view showing how such pawls are punched out of the bar shown in FIG. 5.

SPECIFIC DESCRIPTION As shown in FIG. 1 a latch has a housing 6, here shown partly broken away, mounted on the edge 15 of a motor vehicle door. A lock pin 14 having a head 13 is mounted on the doorpost 16. As the door is closed in the direction of arrow A a lock pawl 3 is pivoted back in the direction of arrow B from the position shown in FIG. 11.

The pawl 3 is mounted on a shaft 1 shown in FIGS. 4 and 5 which is journaled in the housing 6. This shaft 1 is connected at its one end 18 to the operating mechanism housed inside the door and at its other end 2 to the pawl 3. It is formed at end 2 with a pair of parallel and opposite flats 7 separated by a pair of opposite round regions 8.

A straight step ledge 10 separates the pawl 3 into a body portion 19 and a fork portion 20, with a median plane 11 passing longitudinally through the center of the pawl and defining with the step 10 an angle 12 of 102. The body portion 19 is formed with a throughgoing hole 4 formed to snugly receive the end 2 of the shaft 1 since it has flats 7' and rounded portions 8 corresponding to the flats 7 and rounds 8 of the pin end 2. The edge of this hole 4 is beveled at 9 to allow the head 2 of the unhardened pin 1 to be spread out for a very tight fit within the hole 4 of the unhardened pawl 3.

The fork portion 20 of the pawl 3 is formed with a recess 5 opening generally at a right angle to the step 10. The axis 11 is orthogonal to the flats 7.

The body portion 19 has a thickness D which is substantially greater than the thickness d of the fork portion 20. This thickness D is substantially equal to the height b of the hole 4 in the direction of the median plane 11 which is in turn around half as great as the width a of the hole transverse to the axis 11. The distance a corresponds to the diameter of curvature of the regions 8.

The head 13 of the bolt 14 is flattened at 17 on the top where it engages against the straight step of the pawl 3 in the closed position of the door. Thus the bolt head 13 fits between the fork portion 20 and the housing 6.

FIGS. 6 and 7 show how a plurality of such pawls 3 are stamped out of a single elongated rolled profiled steel bar 21. As shown a punch 22 having a cavity 23 of the same outline or configuration as the pawl 3 to be made is oriented to one side of the bar 21 and a die 24 is oriented to the other side. The die 22 is arranged so that the median plane 11 of the cavity 23 lies at an angle of 102 to the longitudinal axis of the profiled bar 21 in order that the step 10 be inclined as shown in FIG. 2. After each punching operation the bar 21 is advanced parallel to the step ledge or flank and in the direction of rolling so that the pawls 3 can be made serially in the fastest manner possible. No subsequent hardening is necessary since, once the pawl 3 is mounted on the end 2 of the pin 1 and this end 2 is spread slightly, an extremely tight fit is formed. Because of to the increased pawl thickness at the body portion 19 canting or displacement of the pawl 3 relative to the pin 1 is virtually impossible.

I claim:

1. A vehicle door latch for securing a vehicle door to a doorpost, said latch comprising:

a rotatable pin extending from the edge of said foor;

a locking element extending from said doorpost; and

a generally flat pivotal lock pawl having a median plane perpendicular to the pawl between edges thereof and formed with a straight stepped ledge inclined to said plane subdividing said pawl into a body portion formed with a hole receiving said pin and a fork portion engageable with said element,

said portions each being of substantially uniform thickness with said body portion being of substantially greater thickness than said fork portion, said hole being intersected by said plane and formed with at least one flat side snugly engaging said pin, said ledge lying at an angle between and to said median plane, said body portion being about twice as thick as said fork portion, said hole being formed with a pair of such flat sides extending parallel to each other and normal to said plane, said flat sides being spaced apart in the direction of said plane by a distance substantially corresponding to the thickness of said body portion.

2. The latch defined in claim 1 wherein said hole has a width orthogonal to said plane which is approximately twice as great as its width in line with said plane.

3. The latch defined in claim 2 wherein said fork portion is formed with a recess directed generally normal to said ledge. 

1. A vehicle door latch for securing a vehicle door to a doorpost, said latch comprising: a rotatable pin extending from the edge of said foor; a locking element extending from said doorpost; and a generally flat pivotal lock pawl having a median plane perpendicular to the pawl between edges thereof and formed with a straight stepped ledge inclined to said plane subdividing said pawl into a body portion formed with a hole receiving said pin and a fork portion engageable with said element, said portions each being of substantially uniform thickness with said body portion being of substantially greater thickness than said fork portion, said hole being intersected by said plane and formed with at least one flat side snugly engaging said pin, said ledge lying at an angle between 100* and 105* to said median plane, said body portion being about twice as thick as said fork portion, said hole being formed with a pair of such flat sides extending parallel to each other and normal to said plane, said flat sides being spaced apart in the direction of said plane by a distance substantially corresponding to the thickness of said body portion.
 2. The latch defined in claim 1 wherein said hole has a width orthogonal to said plane which is approximately twice as great as its width in line with said plane.
 3. The latch defined in claim 2 wherein said fork portion is formed with a recess directed generally normal to said ledge. 